For binding I just use a regular flush trim bit with an aftermarket bearing in my 1/4" router, in the router table. I've been mostly using a 1/2 cutter with a 3/8 bearing for double thick binding, allowing me either a solid colour or a WBW type setup. Stewmac's version of this setup has a very comprehensive bearing set for very precise control over channel width.
The attachment I'd jump for straight away would be the router base. The Dremel branded router bases are embarrassingly bad (at least my one is).
I'm full of dust and guitars - Syd Barrett